Copies of all building permits are sent to the Assessor's Office by the County. All reappraisable new construction is appraised and added to the supplemental roll. Some maintenance items, such as roof repair, may not be considered reappraisable new construction. In appraising new construction, the market value (new base year value) of the new construction is determined and added to the base year value of the existing property. The value of the existing property does not change.

As with a change in ownership, the property owner is then notified of the new assessment and has the right to appeal the value. New construction built without a permit or which does not require a permit (such as landscaping, driveways, or agricultural buildings) is also subject to appraisal. New construction to make a building more accessible to, or usable by, a disabled person may be excluded from reappraisal, if a Claim for Exclusion is filed.